Processing kettle

ABSTRACT

A novel improved processing kettle is disclosed, the kettle comprising an inner hemispherical plate defining an inner lining and an outer hemispherical shell at least partially surrounding the inner plate and forming a steam-jacket space therebetween. Means are disposed through the outer shell providing entrance and egress of steam to and from the steam-jacket so as to heat a product within the kettle that is being mixed. Importantly, at least a portion of the surface of the inner plate communicating with the steam jacket is contemplated to be highly polished so that this surface portion serves to condense steam within the steam-jacket in droplets rather than in a film so as to improve heat transfer characteristics. In the preferred inventive embodiment, a second source of heat is provided for the processing kettle disposed within the kettle itself, the second source of heat comprising a hollow agitator means thus mixing and thermally agitating the product being processed. Thus, the product within the kettle is heated by heat transfer from the inside agitator, as well as heat transfer through the walls of the vessel due to the steam provided in the surrounding steamjacket.

D United States Patent 1 1111 3,739,710 Costa et al. June 19, 1973PROCESSING KETTLE [75] Inventors: Ralph E. Costa, Lutherville; Walter f'Petrakes w. Trevillian, Baltimore, both of leets"!EW'ZQ EZAPMLQ 1931955212 Attorney- Herbert I. Cantor and Denms O. Kraft [73] Assignee: B.H. Hubbert & Son, Inc.,

Baltimore, Md. [571 ABSTRACT [22] Filed: Dee's), 1971 A novel improvedprocessing kettle is disclosed, the kettle comprising an innerhemispherical plate defining PP N05 214,321 an inner lining and an outerhemispherical shell at least partially surrounding the inner plate andforming a 52] us. Cl. 99/348, 165/92, 165/133, Steam-jacket SPacethetehetweett- Means ate disPosed 165/169 through the outer shellproviding entrance and egress 51 Int. Cl. A47j 27/18 steam and from theSteam-jacket as heat a [58] Field 61 Search 99/348, 287, 352, Pmdttctwtthh the kettle that is being ttthttfd- 99/355, 364 371 388, 395 409443; tantly, at least a portion of the surface of the inner plate34/179480 185; 126/343 349 369; communicating with the steam jacket iscontemplated l65/87 88,'90"92, 133, 169; 259/8O 8 l 84 to be highlypolished so that this surface portion serves v n6 DIG 8 to condensesteam within the steam-jacket in droplets rather than in a film so as toimprove heat transfer char- [56] References Cited acteriztics. In th?lpreferred inyierzjtiye erlnbodiment, a 1 secon source 0 eat is prov: eor t e processing U STATES PATENTS kettle disposed within the kettleitself, the second 422,260 2/1890 Stephens.. [65/92 Source f heatcomprising a hollow agitator means thus 831,812 9/1906 webfil 165/90mixing and thermally agitating the product being p 222: g: cessed. Thus,the product within the kettle is heated by 3,1944 165/133 X heattransfer from the inside agitator, as well as heat 2,513,254 6/1950savage at a! 99/348 X transfer through the walls of the vessel due tothe steam 2,607,566 8/1952 1 .Saunders 99/287 ux Provided in theSurrounding Steam-jacket- 2,752, l23 6/1956- Deuschel et al.. 165/133 X1 3,548,926 12/1970 Archer 165/87 6 Chums 2 Drttwmg Figures PatentedJune 19, 1973 2 Sheets-Sheet 2 HHHH HUN UH lllllillliiiiilli- 1PROCESSING KETTLE BACKGROUND OF THE INVENTION This invention generallyrelates to processing kettles and particularly concerns a novelconstruction of a socalled steam-jacketed cooking and processing kettle.

Steam-jacketed cooking and processing kettles and other vessels havefound widespread acceptance in the food preparation industry. Thesurrounding steamjacket typical of such kettles disposed about an innerlining of the vessel effects a quick and easy cooking of most bulk fooditems since steam is directed into the surrounding steam-jacket and, bymeans of heat transfer through the inner plate or wall of the kettle,the product being processed is reasonably evenly heated. The typicalsteam-jacketed kettle of the prior art normally additionally comprises asolid, internal agitator device which serves to mix the product beingprocessed and which further serves to assist in the thermal heattransfer between the external steam-jacket and the product itself.

Processing kettles of the prior art as above-discussed exhibit certaindisadvantages particularly as concerns the efficiency of heat transferinto the product being processed and thus the efficiency and economiesof the product heating process. One such specific disadvantage of thetypical processing kettle concerns the fact that heat is provided onlyfrom the outside of the kettle, i.e., through the inside lining of thekettle wall by means of the surrounding steam-jacket. Accordingly, heattransfer from the entering steam to the product being processed withinthe kettle only occurs about the periphery of the kettle itself, i.e.,from the outside of the kettle into the product being mixed.Additionally, the steam delivered to the surrounding steam jackettypically will condense on the inner wall of the steam jacket itself,i.e., the wall nearest to the inside of the processing kettle, and suchcondensation normally is in the form of a film since the inner surfaceof the steam jacket typically is left in unfinished or rough form. Thiscondensation film has been found to adversely affect the heat transferbetween the steam in the surrounding jacket and the interior of theprocessing vessel.

SUMMARY OF THE INVENTION A need thus exists in the art for an improvedprocessing kettle which does not exhibit the above-describeddisadvantages of prior art construction and which effects a markedlyimproved heat transfer between an external heating source and a productbeing processed within the kettle. It is the primary object of theinstant invention to provide such an improved processing kettle.

A further, more specific, yet equally important object of the instantinvention resides in the provision of an improved processing kettlewherein a source of heat is provided not only on the exterior or outsideof the processing kettle, but is additionally provided in the interiorof the kettle itself, whereby heating of the product being processed canbe accomplished quickly and economically.

An additional though related object of the instant invention concernsthe specific provision of an agitator means disposed within theprocessing kettle itself, the agitator means being steam-heated and thusserving not only as a thermal agitating and mixing mechanism, but

also functioning as a second or internal source of heat to the productbeing processed.

Still another object of the instant invention concerns the provision ofa novel technique whereby the deleterious film-wise condensationtypically occuring on the interior of the steam-jacket of kettles ofprior art construction is substantially eliminated, the heat transferefficiency between the surrounding steam-jacket and the interior of theprocessing vessel thus being greatly improved.

These objects as well as others which will become apparent as thedescription proceeds are implemented by the instant invention which, asaforestated, comprises an improved steam-jacketed processing kettle orvessel. The kettle includes an inner hemispherical head or platedefining an inner lining for the kettle itself with an outerhemispherical shell at least partially surrounding the inner plate andforming a steam-jacket space therebetween into which steam enters andexits. Heat transfer from the steam in the surrounding steamjacket intothe interior of the processing kettle takes place via the inner liningof the kettle as is typical with prior art constructions. importantly,however, at least a portion of the surface of the inner plate or liningcommunicating with the steam-jacket is contemplated to be provided witha high polish, the polished surface defining means to condense steamwithin the steam-jacket in droplets on the surface much in the samemanner as water would bubble on a waxed surface. In this fashion, a filmcondensate is not obtained and the adverse heat-transfer characteristicsof a film condensate are eliminated thus greatly facilitating heattransfer from the steam-jacket through the inner plate into theprocessing kettle.

The novel improved processing kettle of the instant invention furthercontemplates the provision of an internal agitator means disposed withinthe processing kettle, which agitator means serves to mix and tothermally agitate the product being processed. As opposed toconventional constructions, the agitator means of the instant inventionis contemplated to be hollow with steam being caused to flow within thehollowed portions thereof. The hollowed agitator means thus forms aconduit for the passage of steam and the agitator means is therebyheated to provide a heat source that is internal of the kettle and whichis in addition to the outside or external heat source of the kettleprovided by the surrounding steam-jacket.

BRIEF DESCRIPTION OF THE DRAWINGS The invention itself will be betterunderstood and additional features and advantages thereof will becomeapparent by the following'detailed description of a preferred inventiveembodiment, this description referring to the appended sheets ofdrawings, wherein:

FIG. 1 is an elevational plan view, partially broken away forillustrative clarity, of an improved processing kettle embodying thenovel features of the instant invention; and

FIG. 2 is a plan illustration, again partially broken away forillustrative clarity, specifically depicting the details of constructionof the internal hollow agitator means of the instant invention.

Throughout the several views of the drawings, like elements have beendesignated by the same reference numerals.

DETAILED DESCRIPTION OF A PREFERRED INVENTIVE EMBODIMENT Referring nowto the drawings and particularly to FIG. 1 thereof, the novel processingkettle of the instant invention is generally designated by referencenumeral and will be seen to comprise an inner hemispherical head orplate 12 forming a container or vessel, the inner hemispherical plate 12being at least partially surrounded by an outer hemispherical shell 14which forms a steam-jacket space 16 about the inner head 12. Couplings18 and 20 communicating with the steam-jacket 16 through the outerhemispherical shell 14 define means providing entrance and egress ofsteam to and from the interior steam-jacket. So as to protect the kettlefrom unduly high steam pressures within steam-jacket 16, a safety, orblow valve 22 communicates with the interior of the jacket, as isconventional.

During operation of the processing kettle as abovediscussed, steam isintroduced to the steam-jacket 16 via inlet 18 and is withdrawn from thesteam-jacket 16 via outlet 20 through which any condensate that mightform within the steam-jacket may also be discharged. Heat transfer fromthe steam within the surrounding jacket 16 to a product being processedwithin the interior 24 of the vessel itself takes place through theinner hemispherical head or plate 12 and, in this respect, surface 26 ofthe inner hemispherical head 12 is normally constructed or plated withnickel, for example, in an effort to insure good heat transfer from thesurrounding jacket 16, through the inner hemispherical plate 12, andinto the interior 24 of the vessel. Even with such a relativelyexpensive expedient, good heat transfer from the surroundingsteam-jacket 16 to the interior 24 of the vessel 10 is difficult toachieve.

Specifically, the surface 26 of the inner hemispherical head or plate 12which communicates with the steam-jacket 16 is normally of rough orunfinished construction and, as such, steam within the surroundingsteam-jacket 16 tends to condense upon surface 26 in what is termed afilm-wise manner. The existence of this condensate film has been foundto deleteriously affect heat transfer between the surroundingsteamjacket 16 and the interior 24 of the vessel, since, in effect, thisfilm presents a barrier to the heat itself.

As opposed to the conventional construction of the inner hemisphericalplate or head 12 and specifically of the interior wall 26 thereof asabove-discussed, the instant invention contemplates to polish at least aportion of surface 26 of the inner hemispherical head or plate 12 suchthat this surface portion defines a means to condense steam within thesteam-jacket 16 in droplets on the surface rather than as a filmcondensate. With such a polished surface, steam within the surroundingjacket 16 still condenses on surface 26, but the condensate in in theform of droplets or bubbles rather than in the form of a film and, assuch, the barrier affect of a condensate film no longer exists and heattransfer between the surrounding steam-jacket 16 and the interior 24 ofthe vessel 10 is markedly improved.

The surface portion 26 of the inner hemispherical head or plate 12preferably is polished by means of any suitable technique such as a beltgrinder having an abrasiveness of 180 grit, and then followed by finebuffing with cloth and rouge. It has been found that the coefficient ofheat transfer from the surrounding steamjacket 16 into the interior 24of vessel 10 can be up to eight times greater with a polished surface asabovedescribed than is the coefficient of heat transfer through anunpolished surface wherein the film-like condensate barrier layeroccurs. And, with the utilization of the polished interior surfaceportion, the processing kettle of the instant invention no longerrequires a formation of a nickel plating or coating on surface 26,surface 26 as well as the remaining portions of the inner hemisphericalplate or head 12 being constructed only of conventional stainless steel.

When utilizing such a polished internal surface Applicants have foundthat the greatest heat transfer advantages can be obtained when thesteam introduced into the steam-jacket 16 includes a conventionalcleaning agent, which cleaning agent tends to keep the polished surface26 clean of contaminants and insure the drop-wise condensation of steamthereon.

The processing vessel of the instant invention further includes anagitator means generally designated 26 and disposed within the interior24 of the vessel 10, the agitator means serving to stir and thermallyagitate and mix the product being processed. In this respect, rotarymotion is provided to the agitator 26 by means of an external electricmotor 28 and an associated rotary coupling joint 30 containing a typicalworm-drive gearing arrangement 32, for example. as can best be seen froman inspection of FIG. 2. Specifically, the worm-drive from the electricmotor 28 is adapted to engage the illustrated ring gear disposed about avertical shaft 34 of the agitator means 26, the motor 28 as well as therotary coupling joint or mechanism 30 being disposed in a position abovethe interior 24 of the processing vessel or kettle 10 on an elevatedplatform generally designated 36, which platform can be withdrawn fromthe processing kettle 10 by non-illustrated means so as to likewisewithdraw the agitator means 26 from the interior 24 of the kettle. As isconventional, downwardly depending fixed fingers 38 may be disposed fromthe platform 36 so as to assist the agitator means 26 in breaking uplarge particles of food or other product being processed within theinterior 24 of the vessel 10. Additionally, a hinged cover plate or thelike could be disposed about the top of the processing kettle 10 inconventional manner, if so desired.

Referring specifically, now, to FIG. 2 of the appended drawings, thenovel construction of the agitator means 26 of the instant invention canbe seen. Specifically, the elongated vertical shaft 34 of the agitatormeans 26 is contemplated to be of hollow construction and a hollowarcuate mixing member 40 which follows the contour of the inner liningor head 12 of the vessel is coupled to the elongated shaft 34 of theagitator means 26 and communicates with the interior thereof. In thepreferred embodiment of the agitator means 26, hollow conduits 42 aredisposed between the hollow vertical shaft 34 and locations along thelength of the hollow arcuate mixing member 40, conduits 42 definingbrace members. Conventional steam air valves 43 may be coupled to themixing member 40 as shown.

At the lower-most point of the hollow arcuate mixing member 40, acondensate collector chamber 44 is disposed, the purpose of which willbecome apparent from the description hereinbelow. Finally, the hollowagitator means 26 of the instant invention will be seen to include anelongated hollow tube 46 disposed concentrically within the hollow shaft34 and communicating at one end thereof with the interior of the arcuatemixing member 40 and specifically with the condensate collector chamber44. The hollow tube 46 exits the agitator means 26 at an orifice 48provided at the top of the agitator means 26 and it will further be seenthat an orifice 50, also provided at the top of agitator means 26communicates with the interior of the elongated hollow shaft 34. Orifice50 defines a means providing entrance of steam to the agitator means 26,while orifice 48 defines means providing an exit of steam and condensatefrom the agitator means 26, orifices 48 and 50 being physically disposedin a coupling block or member 52 of suitable construction.

In operation, a product to be processed by the kettle of the instantinvention is disposed within the interior 24 of the kettle. Steam isthen directed into the surrounding steam-jacket 16 in the fashionabovedescribed and heat transfer takes place into the product beingprocessed via the inner hemispherical plate 12. The agitator assembly 26is simultaneously caused to be rotated by motor 28 and the rotary gearor coupling box 30, the rotational movement of the agitator serving tomix and agitate the product within the interior 24 of the kettle 10 andfurther serving to improve the heat transfer between the steam-jacket l6and the product. The agitator means 26 itself, however, will be seen tocomprise a second or internal heat source for heating the product.

In this respect, steam is additionally introduced into inlet 50above-described, the steam then flowing downwardly through thevertically extending hollow shaft 34 generally along the paths depictedby the arrows within the shaft 34. The steam flows through each of thestructural conduit members 42 and into the arcuate portion 40 of theagitator means, all surfaces of the agitator means 26 defining heattransfer surfaces for transferring heat from the steam into the productbeing processed.

At least a portion or some percentage of the steam within the agitatormeans 26 will, of course, condense within the agitator means 26 and suchcondensate flows into the condensate collector chamber 44 due to gravityand due to the configuration of the hollow arcuate mixing member 40. Thecondensate collector chamber 44 also functions as a general collectingchamber for the steam to be expelled from within the interior ofagitator means 26 itself and, as above-discussed, the lower portion ofthe internal hollow tube 46 communicates with the collector chamber 44.Accordingly, steam to be discharged from agitator 26 as well as anycondensate that has formed within agitator means 26 is taken up from thecondensate collector chamber 44 through the internal hollow tube 46 andis expelled through the steam outlet orifice or opening 48. In thisfashion, the agitator means 26 of the instant invention defines anadditional heat source for the processing vessel, this additional heatsource being an internal heat source and assisting with the heating ofthe product within the interior of the vessel.

In actual use of the above-described apparatus, the provision of aninternal and hollow steam-heated agitator means effecting a second andinternal heat source has been seen to increase the heating efficiency ofthe product being processed within the interior 24 of the vessel 10 byas much as 25 percent, thus greatly reducing the amount of heating timerequired.

Continuing with the description of the invention and now referring againspecifically to FIG. 1 of the appended drawings, the agitator means 26is contemplated to include a plurality of scraper blades 54 as isconventional, which blades can be constructed of any suitable materialsuch as Teflon, for example, so as to scrape any stagnant film formed inthe interior of the vessel and thus to further increase the efficiencyof heat transfer between the surrounding steam-jacket 16 and the vesselinterior. Additionally, and as is conventional, an outlet 56 is providedat the bottom of the processing kettle 10 which communicates with theinterior 24 of the kettle 10 through the inner and outer hemisphericalplates or linings l2 and 14, respectively. Outlet 56 serves to providean exit path for processed material from the interior of the kettle 10.

Throughout the foregoing specification, the novel improved processingkettle of the instant invention has been described only in terms of apreferred inventive embodiment and it should be understood that theinvention is not limited to the exact details of constructions shown anddescribed herein for obvious modifications will occur to persons skilledin the art. For example, while steam was specifically discussed as theheating exchange medium for the kettle and agitator, it should beapparent that other suitable heat exchange mediums such as water orother fluids could be used. Or, for that matter, and if desired, thehollow agitator and/or the kettle jacket could be utilized as amechanism to effect cooling rather than heating of the material beingprocessed within the kettle. In this respect, a heat exchange mediumsuch as a refrigerated fluid could be passed through the interior of theagitator and/or through the jacket of the kettle.

It should now be appreciated that the objects initially set forth at theoutset of this specification have now been successfully achieved.

Accordingly, What is claimed is:

1. An improved processing kettle comprising, in combination, an innerhemispherical plate defining an inner lining for the processing kettle,an outer hemispherical shell at least partially surrounding said innerplate and forming a jacket space therebetween, means through said outershell providing entrance and egress of a heat exchange medium to andfrom said jacket, and wherein at least a portion of the surface of saidinner plate communicating with said jacket is a polished surfacedefining means to condense said heat exchange medium within said jacketin droplets on said surface whereby heat transfer between said jacketand the processing kettle through said inner plate is facilitated, saidkettle further including a substantially hollow agitator means disposedinside the kettle for stirring a product to be processed therewithin,said hollow agitator means comprising an elongated hollow vertical shaftand a hollow arcuate mixing member attached thereto and substantiallyfollowing the contours of the inner lining of the kettle with theinterior of said hollow mixing member communicating with the interior ofsaid hollow vertical shaft, an elongated hollow tube disposed withinsaid hollow shaft and extending downwardly into said hollow mixingmember at the region of its attachment to said hollow vertical shaft,said tube having an opening at its lowermost end such that the interiorof said tube communicates with the interior of said hollow mixing memberat said attachment region, said kettle further including means coupledto a respective one of said hollow shaft and said hollow tube forproviding entrance and egress of a heat exchange medium into said hollowagitator means whereby said agitator means defines an additional heatexchange source for the processing kettle with heat being transferred toa product within the processing kettle from the external jacket and withheat exchange further being effected by the internal agitator means.

2. A processing kettle as defined in claim 1, further including hollowconduits disposed between said hollow vertical shaft and locations alongthe length of said hollow arcuate mixing member, said conduits definingbrace members for said agitator means as well as additional paths forthe circulation of said heat medium within said agitator means.

3. A processing kettle as defined in claim 1, further including acondensate collector chamber means for said heat exchange mediumdisposed in said hollow mixing member in the region of communication ofsaid elongated hollow tube and said hollow mixing member.

4. A hollow agitator means for use with a processing kettle, said hollowagitator means being adapted to be disposed inside the kettle forstirring a product to be processed therewithin, said agitator meanscomprising an elongated hollow vertical shaft and a hollow arcuatemixing member attached thereto and substantially following the contoursof the kettle with the interior of said hollow mixing membercommunicating with the interior of said hollow vertical shaft, anelongated hollow tube disposed within said hollow shaft and extendingdownwardly into said hollow mixing member at the region of itsattachment to said hollow shaft, said tube having an opening at itslowermost end such that the interior of said tube communicates with theinterior of said hollow mixing member at said attachment region, andmeans coupled to a respective one of said hollow shaft and said hollowtube for providing entrance and egress of a heat exchange medium to saidhollow agitator means, whereby said agitator means defines a heatexchange source for the processing kettle with heat exchange beingeffected between said agitator means and the product within theprocessing kettle.

5. An agitator as defined in claim 4, further including hollow conduitsdisposed between said hollow vertical shaft and locations along thelength of said hollow arcuate mixing member, said conduits definingbrace members for said agitator means as well as additional paths forthe circulation of said heat medium.

6. An agitator as defined in claim 4, further including a condensatecollector chamber means for said heat exchange medium disposed in saidhollow mixing member in the region of communication of said elongatedhollow tube and said hollow mixing member.

1. An improved processing kettle comprising, in combination, an innerhemispherical plate defining an inner lining for the processing kettle,an outer hemispherical shell at least partially surrounding said innerplate and forming a jacket space therebetween, means through said outershell providing entrance and egress of a heat exchange medium to andfrom said jacket, and wherein at least a portion of the surface of saidinner plate communicating with said jacket is a polished surfacedefining means to condense said heat exchange medium within said jacketin droplets on said surface whereby heat transfer between said jacketand the processing kettle through said inner plate is facilitated, saidkettle further including a substantially hollow agitator means disposedinside the kettle for stirring a product to be processed therewithin,said hollow agitator means comprising an elongated hollow vertical shaftand a hollow arcuate mixing member attached thereto and substantiallyfollowing the contours of the inner lining of the kettle with theinterior of said hollow mixing member communicating with the interior ofsaid hollow vertical shaft, an elongated hollow tube disposed withinsaid hollow shaft and extending downwardly into said hollow mixingmember at the region of its attachment to said hollow vertical shaft,said tube having an opening at its lowermost end such that the interiorof said tube communicates with the interior of said hollow mixing memberat said attachment region, said kettle further including means coupledto a respective one of said hollow shaft and said hollow tube forproviding entrance and egress of a heat exchange medium into said hollowagitator means whereby said agitator means defines an additional heatexchange source for the processing kettle with heat being transferred toa product within the processing kettle from the external jacket and withheat exchange further being effected by the internal agitator means. 2.A processing kettle as defined in claim 1, further including hollowconduits disposed between said hollow vertical shaft and locations alongthe length of said hollow arcuate mixing member, said conduits definingbrace members for said agitator means as well as additional paths forthe circulation of said heat medium within said agitator means.
 3. Aprocessing kettle as defined in claim 1, further including a condensatecollector chamber means for said heat exchange medium disposed in saidhollow mixing member in the region of communication of said elongatedhollow tube and said hollow mixing member.
 4. A hollow agitator meansfor use with a processing kettle, said hollow agitator means beingadapted to be disposed inside the kettle for stirring a product to beprocessed therewithin, said agitator means comprising an elongatedhollow vertical shaft and a hollow arcuate mixing member attachedthereto and substantially following the contours of the kettlE with theinterior of said hollow mixing member communicating with the interior ofsaid hollow vertical shaft, an elongated hollow tube disposed withinsaid hollow shaft and extending downwardly into said hollow mixingmember at the region of its attachment to said hollow shaft, said tubehaving an opening at its lowermost end such that the interior of saidtube communicates with the interior of said hollow mixing member at saidattachment region, and means coupled to a respective one of said hollowshaft and said hollow tube for providing entrance and egress of a heatexchange medium to said hollow agitator means, whereby said agitatormeans defines a heat exchange source for the processing kettle with heatexchange being effected between said agitator means and the productwithin the processing kettle.
 5. An agitator as defined in claim 4,further including hollow conduits disposed between said hollow verticalshaft and locations along the length of said hollow arcuate mixingmember, said conduits defining brace members for said agitator means aswell as additional paths for the circulation of said heat medium.
 6. Anagitator as defined in claim 4, further including a condensate collectorchamber means for said heat exchange medium disposed in said hollowmixing member in the region of communication of said elongated hollowtube and said hollow mixing member.